The present invention concerns an electronic circuit which functions simultaneously as a phase detector and low pass filter. Phase detectors of various types are well known in the electronic arts. They find utility, among other places, in circuits for decoding stereophonic signals in stereophonic equipment such as tape recorders, phonographs, and radios.
Low pass filters are also well known in the electronic arts, and they find utility in a wide variety of electronic signal processing circuits.
Prior art phase detector circuits have been fabricated in partially integrated circuit form, but until the present invention certain of the circuit components have had to be connected to the integrated circuit off-chip, thus considerably increasing the cost of the phase detector circuit in the particular application.
The combined phase detector and low pass filter of the present invention may be fabricated in a completely integrated circuit form. Thus the external components necessary in prior art circuits can be completely eliminated. The result is a circuit of substantially increased commercial importance.